// Copyright 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CONTENT_CHILD_CHILD_RESOURCE_MESSAGE_FILTER_H_
#define CONTENT_CHILD_CHILD_RESOURCE_MESSAGE_FILTER_H_

#include "base/macros.h"
#include "base/memory/ref_counted.h"
#include "ipc/message_filter.h"

namespace base {
class SingleThreadTaskRunner;
}

namespace content {
class ResourceDispatcher;

// Supplies ResourceDispatcher with timestamps for some resource messages.
//
// Background: ResourceDispatcher converts browser process time to child
// process time. This is done to achieve coherent timeline. Conversion is
// a linear transformation such that given browser process time range is
// mapped to corresponding child process time range. Timestamps for child
// process time range should be taken by IO thread when resource messages
// arrive. Otherwise, timestamps may be affected by long rendering / JS task.
//
// When specific message is processed by this filter, new task charged
// with timestamp is posted to main thread. This task is processed just before
// resource message and invokes ResourceDispatcher::set_io_timestamp.
class ChildResourceMessageFilter : public IPC::MessageFilter {
public:
    explicit ChildResourceMessageFilter(ResourceDispatcher* resource_dispatcher);

    // IPC::MessageFilter implementation.
    bool OnMessageReceived(const IPC::Message& message) override;

    void SetMainThreadTaskRunner(
        scoped_refptr<base::SingleThreadTaskRunner> main_thread_task_runner)
    {
        main_thread_task_runner_ = main_thread_task_runner;
    }

private:
    ~ChildResourceMessageFilter() override;

    scoped_refptr<base::SingleThreadTaskRunner> main_thread_task_runner_;
    ResourceDispatcher* resource_dispatcher_;

    DISALLOW_COPY_AND_ASSIGN(ChildResourceMessageFilter);
};

} // namespace content

#endif // CONTENT_CHILD_CHILD_RESOURCE_MESSAGE_FILTER_H_
